Opening files on Bb

HTML file

Clicking will open it.

Zip file

Clicking will open it provided it was properly uploaded

PDF file

Clicking will open it with Acrobat or Acrobat Reader if that is on your computer.

Word doc

Clicking on it will call the Download Manager and then automatically open the file in Word on your computer.

WordPerfect.wpd

Clicking on it will call the Download Manager and then automatically open the file in WordPerfect on your computer.

I do not have WordPerfect. So I get the following screen:

Often, you get this screen also when you click on a media file.
Select one of the three available options. Save it to disk is probably most desirable. Then open the file with an appropriate viewer.

See plug-ins / viewers. They exist not only for audio and video files, but also, on the Microsoft site, for applications you do not own.